Earth

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Earth
Earthrise.jpeg
Earth, seen from Luna.
Galactic
Coordinates
Region Central Orion Spur
Sector Sol Greater Expansion Area
Core distance 212.5 Exametres
(22,462 light years)
Astronomical
Absolute name Sol III
Aphelion 152,098 Mm (1 AU)
Perihelion 147,098 Mm (1 AU)
Semi-major axis 148,598 Mm (1 AU)
Orbital speed 29.78 kms-1
Orbital period 365.26 days
Rotation period 23:56 hours
Axial tilt 23°
Physical
Age 4.45 Gy
Type Terrestrial
Mean radius 6,371.0 km
Surface gravity 9.798 ms-2
(0.99732 g)
Atmospheric
Surface pressure 101.325 kPa
Composition 78.08% nitrogen gas
20.95% oxygen gas
~ 1% water vapor
< 1% other gases
Median temperature 15.3ºC
288K
Habitation
Population 14,383,937,534
Government Federal Syndicate of Terra
Colonised Prehistoric
Capital Geneva
Major settlements Lagos, Mumbai, New York, Paris, Sao Paulo, Shanghai, Sydney, Tokyo, Toronto, London

Earth, absolute name Sol III, is the third planet from the type-G star Sol. The terrestrial planet was formed in 4.5 billion BCE along with its star, being the fifth largest planetary body in its solar system, and also the densest. It measures in at 12,716 kilometres in diameter.

Earth is the homeworld of Terrankind.

Astronomy[edit | edit source]

Earth orbits at an average distance of 149,598,261 kilometres from its star, completing one revolution once every 365.25 days. Earth rotates around its own axis roughly every 24 hours, every such rotation marking a day passing.

Earth has only one natural satellite, Luna, formed from a cataclysmic impact event in the planet's past.

Biosphere[edit | edit source]

Earth's life emerged around 3.0-3.5 billion years ago, and is based on carbon chemistry. Most of its life forms are aquatic animals residing in the planet's oceans and wetlands; This is likely to be where primordial life began.

Between 200 and 65 million years ago in its past, the planet was dominated by enormous terrestrial lizards, known as dinosaurs, however a mass extinction event led to their demise, allowing mammalian organisms to take the lead, then leading to their dominance and the derivative evolution of Earth's sentient species.

Civilisation[edit | edit source]

Main article: Terran

Terran civilisation first formed on Earth and is mostly saturated in areas with milder climates, though advances in technology allowed many terrans to live in harsher conditions on the planet. Up until the Treaty of Proxima in 2121, Terran people lived in numerous seperate sovereign states.

As of 2700 the planet's population was set at approximately 14 billion inhabitants, and is expected to stay mostly stable. 80% of the population lives in urban centres.

Structure[edit | edit source]

The terrestrial planet is broken up into four distinct geological layers: The crust, mantle, outer and the inner core.

The outer core generates a magnetic field around Earth, protecting it from solar winds and cosmic rays, which would otherwise damage the planet's atmosphere and in turn, any living organisms on the ground.

Geography[edit | edit source]

Earth is a moist temperate garden world, with water covering over two-thirds of its surface.

Climate[edit | edit source]

The planet's temperature averages at approximately 15 degrees Celsius (288 degrees Kelvin), with a typical range of between -20 degrees to 30 degrees, though more extreme temperatures exist at its equator and poles. The planet's large oceans help moderate temperatures throughout the planet. Weather systems in different climates vary throughout its year as a result of Earth's rotation around the Sun and the tilt of its rotational axis.

Although Earth does have variations of approximately 5 million kilometres in its orbit around Sol, the climatic effects are rather negligible.

Physical Geography[edit | edit source]

Most of the planet's surface is covered in water, allowing the formation of complex organic molecules. The extensive amount of water has caused populations in the past to dub it "The Blue Planet" in comparison to other planets in its system. Its oceans are dissolved with salt, although regions at freshwater river deltas tend to have a much lower saline content. The oceans also harbour oceanic currents, formed from the exchange of cold water and warm water across its latitudes.

Most of its crust is made of sedimentary rocks, though also with a mix of igneous rocks, more commonly near its tectonic plate boundaries.

Plate tectonics shift and move its landmasses around, with collisions between plates forming large mountain ridges. Strong weather forces over long periods of time reshape the landscape as well.

Atmosphere[edit | edit source]

Earth's atmosphere has five distinct layers, which help in keeping the planet hospitable. Its atmosphere allows the moderation of the climate on the surface, and also protect it against outside hazards such as blocking and absorbing radiation or burning up meteors.

Its troposphere, the lowest and thinnest of the layers, is composed of roughly 80% nitrogen gas and 20% oxygen gas, the latter helping the survival of any animal species. The stratosphere, above the troposphere, contains an ozone layer which protects the surface of the planet from harmful radiation from its sun Sol.

The atmosphere contains an extensive network of trade winds which transports moisture all over the planet. Precipitation can vary greatly across the surface of the planet.

Resources[edit | edit source]

Being a garden world, Earth is a favourable location for the production of food, both for crops and livestock.

Mining grants access to other resources. Hydrocarbon fuels are prevelant due to the planet's wetlands in the past, such as coal, natural gas and oil, although reserves have been largely used up during Terran industralisation. Other minerals present on the planet include vast quantities of metals such as aluminium, copper and silicon, as well as rarer elements like uranium.

The planet's seawater can be mass desalinised and broken down molecularly to fuel deuterium-tritium fusion reactors.

Hazards[edit | edit source]

Although not as extreme as the other planets in its system, Earth's weather can be dangerous without proper preparation due to its unpredictability. Many of Earth's weather is strongly fueled by its massive amount of water present on its surface. Blizzards and storms are common throughout the planet. Typhoons, massive storms that form in warm waters in the equator, slam into coastal areas delivering torrential rain, frightening winds and storm surges that can disrupt economies and societies. Other weather anomalies such as hail and tornadoes also occur on Earth.

The planet's highly active tectonic plates regularly produce powerful earthquakes and active volcanic activity, though of the occurring earthquakes relatively few are devastating. Most seismic activity is concentrated around an area dubbed the Ring of Fire. Subsequently, about 75% of Earth's volcanoes are concentrated within this region. Undersea earthquakes can also produce massive waves known as tsunamis, sandblasting coastlines on impact.

In the scope of space, Earth's system harbours a considerably near asteroid field, although impacts are mitigated from its unusually large moon and the gas giant Jupiter.